Co-reporter:Shuang Fan, Wenjun Dong, Xiubing Huang, Hongyi Gao, Jingjing Wang, Zhaokui Jin, Jia Tang, and Ge Wang
ACS Catalysis January 6, 2017 Volume 7(Issue 1) pp:243-243
Publication Date(Web):November 23, 2016
DOI:10.1021/acscatal.6b02614
The multifunctional design of heterogeneous catalysts which can realize the selective oxidation of C–H bonds with oxygen at low temperature is of crucial importance in the catalysis community. Here, we report the designed synthesis of Cu-CuFe2O4@HKUST-1 heterostructures that is highly active for the selective oxidation of benzylic C–H bonds under mild conditions (60 °C). In the synthetic process, the Cu(0) component of Cu-CuFe2O4 nanoparticles gradually released Cu2+ ions which were in situ transformed into the HKUST-1 shell. The high activity can be attributed to a rationally multifunctional design of Cu-CuFe2O4@HKUST-1 heterostructures, in which Cu-CuFe2O4 can provide multiple active sites while HKUST-1 attracts and preconcentrates molecular oxygen. Notably, the catalytic performance under optimized reaction conditions (60 °C) was achieved in the oxidation of fluorene to fluorenone (conversion: > 99%, selectivity: > 99%). Furthermore, the Cu-CuFe2O4@HKUST-1 catalyst could be easily recovered by magnetic separation and reused for 10 times without significant loss of catalytic activity.Keywords: benzylic C−H oxidation; Cu-CuFe2O4@HKUST-1; in situ transformation; mild reaction conditions; multifunctional design;
Co-reporter:Xiubing Huang;Liping Liu;Hongyi Gao;Wenjun Dong;Mu Yang
Green Chemistry (1999-Present) 2017 vol. 19(Issue 3) pp:769-777
Publication Date(Web):2017/02/06
DOI:10.1039/C6GC02065H
A facile and scaled-up synthesis route to hierarchically nanostructured transition metal oxides with desirable properties is of great practical importance because of their excellent performance as heterogeneous catalysts in organic synthesis. In this work, hierarchically nanostructured MnCo2O4 nanorods with multi-nanopores have been prepared by a facile co-precipitation method using oxalic acid as a precipitant and through their consequent removal by calcination. When evaluated as catalysts for the synthesis of N-benzylideneaniline from benzyl alcohol and aniline, the as-prepared hierarchically nanostructured MnCo2O4-500 nanorods possessed high conversion (90.9%) of benzyl alcohol and selectivity (95.4%) of N-benzylideneaniline at 60 °C even under air for 15 h, which can be attributed to the appropriate and similar ratios of Mn2+/Mn3+ (1.36 : 1) and Co2+/Co3+ (1.35 : 1) with excellent synergistic effects. The proposed mechanism reveals that the benzyl alcohol is initially dehydrogenated to benzaldehyde which then reacts with another molecule of aniline to form N-benzylideneaniline. The MnCo2O4-500 nanorods can also be easily recycled without significant loss in catalytic activity for at least 4 cycles. Our findings could provide some guidance on the design of nanostructured spinel-type metal oxide catalysts with better synergistic effects in organic synthesis.
Co-reporter:Jiawei Wang;Xilai Jia;Dimberu G. Atinafu;Mingshuo Wang;Yunfeng Lu
Journal of Materials Chemistry A 2017 vol. 5(Issue 46) pp:24321-24328
Publication Date(Web):2017/11/28
DOI:10.1039/C7TA05594C
Mesoporous carbons with high porosity, large specific surface areas and a certain degree of graphitization were facilely prepared via carbonization of sucrose at different temperatures of 700 °C (C-700), 800 °C (C-800) and 900 °C (C-900) and were used as supporting frameworks for phase change materials (PCMs) loading paraffin. The as-prepared carbons had high loading capacity of paraffin as demonstrated by leakage tests. The paraffin loading capacity of C-700, C-800 and C-900 reached up to 88.8 wt%, 91.7 wt% and 90.6 wt% respectively without leakage, and the corresponding latent heats were 103.0%, 104.5% and 102.9% that of pure paraffin with the same actual paraffin amount, showing improved latent heat. TG results showed that the as-prepared PCMs had better thermal stability and their good thermal cycling stability was demonstrated by thermal cycling tests after 50 cycles. Furthermore, the thermal conductivity of the composite PCMs improved to a certain degree compared with that of pure paraffin.
Co-reporter:Xiubing Huang;Guixia Zhao
Journal of Materials Chemistry A 2017 vol. 5(Issue 47) pp:24631-24635
Publication Date(Web):2017/12/05
DOI:10.1039/C7TA08734A
Here, a facile strategy is reported for attaching a sub-nano cobalt oxide catalyst onto a WO3 surface using Co-EDTA as precursor, which greatly improved the WO3 performance in OER to give a photocatalytic O2 evolution rate of 314.3 μmol h−1 and a photocurrent density of around 2.07 mA cm−2 at 1.3 V vs. Ag/AgCl in photoelectrochemical water oxidation.
Co-reporter:Radoelizo S. Andriamitantsoa;Wenjun Dong;Hongyi Gao
New Journal of Chemistry (1998-Present) 2017 vol. 41(Issue 4) pp:1790-1797
Publication Date(Web):2017/02/13
DOI:10.1039/C6NJ03034C
An organic–inorganic hybrid porous metal–organic gel (MOG) based on Cr3+ and bridging benzene-1,3,5-tricarboxylic acid (BTC) was synthesized. The MOG exhibited good porosity, flexibility and a high surface area to encapsulate stearic acid (SA) for phase change materials (PCMs). The porosity of MOG-100 (Cr) guaranteed an excellent thermal stability of the encapsulated stearic acid. No leakage of PCMs was observed from the MOG even after heating the SA@MOG-100 (Cr) composites beyond their melting point. A maximum weight percentage as high as 90% of stearic acid has been achieved without leakage. The melting temperature of the SA@MOG-100 (Cr) composite was 71.9 °C and the total latent heat of fusion of the composite was measured to be in the range of 101–189.3 kJ kg−1. They present excellent thermal recyclability within at least 15 melting/freezing cycles.
Co-reporter:Rui Dang, Xilai Jia, Peng Wang, Xiaowei Zhang, ... Ge Wang
Chinese Chemical Letters 2017 Volume 28, Issue 12(Volume 28, Issue 12) pp:
Publication Date(Web):1 December 2017
DOI:10.1016/j.cclet.2017.09.064
The peony-like CuO micro/nanostructures were fabricated by a facile hydrothermal approach. The peony-like CuO micro/nanostructures about 3 –5 μm in diameter were assembled by CuO nanoplates. These CuO nanoplates, as the building block, were self-assembled into multilayer structures under the action of ethidene diamine, and then grew into uniform peony-like CuO architecture. The novel peony-like CuO micro/nanostructures exhibit a high cycling stability and improved rate capability. The peony-like CuO micro/nanostructures electrodes show a high reversible capacity of 456 mAh/g after 200 cycles, much higher than that of the commercial CuO nanocrystals at a current 0.1 C. The excellent electrochemical performance of peony-like CuO micro/nanostructures might be ascribed to the unique assembly structure, which not only provide large electrode/electrolyte contact area to accelerate the lithiation reaction, but also the interval between the multilayer structures of CuO nanoplates electrode could provide enough interior space to accommodate the volume change during Li+ insertion and de-insertion process.Download high-res image (308KB)Download full-size imagePeony-like CuO micro/nanostructure was fabricated by a facile hydrothermal approach. The peony-like CuO was assembled by CuO nanoplates. This novel peony-like CuO exhibited a high cycling stability and improved rate capability.
Co-reporter:Lining Fang, Ge Wang, Wanchun Guo
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2017 Volume 533(Volume 533) pp:
Publication Date(Web):20 November 2017
DOI:10.1016/j.colsurfa.2017.07.060
Magnetically recoverable heteropoly acids (HPAs) exhibit high activity for oxidation reactions. However, HPA species immobilized onto magnetic supports commonly suffer from the loss of active species into reaction solutions due to the weak affinity of the supports for active species. Herein, core-shell Fe3O4@thermally crosslinked PANI@Tunstophoric acid (Fe3O4@TC-PANI@TPA) nanostructures were rationally synthesized based on a PVP-mediated surface polymerization strategy and a subsequent thermal treatment process. Uniform PANI shell and TPA species were successively deposited onto Fe3O4 nanoclusters, followed by a thermal crosslinked treatment of PANI shell. Spatial confinement of high dispersed TPA sites within thermally crosslinked PANI shell could largely enhance their solvent tolerance against the loss of active TPA sites accompanied by the dissolution of some non-crosslinked PANI chains during catalytic transformations. As expected, the Fe3O4@TC-PANI@TPA catalyst exhibited high activity, facile magnetic recoverability, and robust stability for green epoxidation of cis-cyclooctene using ethanol as a solvent and H2O2 as an oxidant.Download high-res image (283KB)Download full-size image
Co-reporter:Xilai Jia, Jie Wang, Xiao Zhu, Tihong Wang, Fan Yang, Wenjun Dong, Ge Wang, Haitao Yang, Fei Wei
Journal of Alloys and Compounds 2017 Volume 697(Volume 697) pp:
Publication Date(Web):15 March 2017
DOI:10.1016/j.jallcom.2016.11.421
•Lightweight, compressible, and magnetic composite aerogel were prepared by an in-situ hydro-thermal method.•Porous Fe3O4 were threaded by CNTs, leading to an integrated structure.•By rational combination of Fe3O4 and CNTs, the composite displayed enhanced microwave absorption.Inorganic composites with mechanical flexibility are desired in synthesis of advanced materials for multifunctional applications. Here, we demonstrated the synthesis of a lightweight and flexible composite aerogel composed of carbon nanotubes (CNTs) and mesoporous iron oxide (Fe3O4) using an in-situ growth method. CNTs serve as frameworks for the growth of magnetic ferrite nanoparticles; while the growth of the magnetic nanoparticles crosslinks CNTs into an integrated structure. Therefore, mesoporous Fe3O4 particles are threaded by CNTs, leading to formation of the monolithic magnetic foam with a high particle loading of more than 88 wt%. This magnetic foam is highly porous, effective for microwave absorption. Based on the rational combination of Fe3O4 and CNTs, the composite material can offer excellent microwave absorbing performance, particularly in the low-frequency range of 3–5 GHz. Moreover, the porous composite aerogel can be compacted into a flexible magnetic nanopaper. Because of the structure properties, the composite may be used in many other applications such as energy storage, catalyst, and biochemistry.
Co-reporter:Xin Liu, Rui Dang, Wenjun Dong, Xiubing Huang, Jia Tang, Hongyi Gao, Ge Wang
Applied Catalysis B: Environmental 2017 Volume 209(Volume 209) pp:
Publication Date(Web):15 July 2017
DOI:10.1016/j.apcatb.2017.02.073
•A hierarchical sandwich-like TiO2NS@MIL-100(Fe) heterostructure was developed through a self-assembled method by incorporating MIL-100(Fe) into TiO2NS.•TiO2NS@MIL-100(Fe) nanocomposites exhibit high adsorption ability owing to the introduction of MIL-100(Fe) with the porous tunnel adsorbing organic molecules.•The resulting sandwich-like TiO2NS@MIL-100(Fe) nanocomposites exhibited enhanced the photocatalytic activity due to the interfaces of TiO2NS and MIL-100(Fe) which provide platforms for rapid photoexcited electrons transfer, facilitated separation of electron-hole pairs.Hierarchical heterostructures with specific compositions, morphology and functionalities are important for applications in many fields such as catalysis, energy storage and conversion. Herein, hierarchical sandwich-like heterostructures were prepared by a self-assembly method of growing MIL-100(Fe) on host two dimensional (2D) TiO2 nanosheets (TiO2NS). The introduction of porous MIL-100(Fe) on TiO2NS improves the adsorption ability of nanocomposites owing to the porous tunnel adsorbing organic molecules and high surface area. In addition, the interfaces of TiO2NS and MIL-100(Fe) provide platforms for rapid photoexcited electrons transfer and enhance the photocatalytic activity of TiO2NS@MIL-100(Fe) nanocomposites. The resulting sandwich-like TiO2NS@MIL-100(Fe) nanocomposites with enhanced adsorption ability and superior separation of photogenerated electron-hole pairs exhibited improved photoactivity toward degradation of methylene blue dye (MB) under visible light (λ ≥ 420 nm). TiO2NS@MIL-100(Fe) nanocomposites offer an useful platform to integrate photocatalytic semiconductor and porous MOFs into hierarchical nanostructures with high surface areas and efficient electrons transfer for enhanced photocatalytic performance.The sandwich-like heterostructural TiO2NS@MIL-100(Fe) nanocomposites exhibit high adsorption ability and enhanced photocatalytic property. The porous MIL-100(Fe) on TiO2NS improves the adsorption ability of nanocomposites owing to the porous tunnel adsorbing organic molecules, and the interfaces of TiO2NS and MIL-100(Fe) provide platforms for rapid photoexcited electrons transfer from MIL-100(Fe) to TiO2NS and enhance the photocatalytic activity.
Co-reporter:Jia Tang, Mu Yang, Fang Yu, Xingyu Chen, Li Tan, Ge Wang
Applied Energy 2017 Volume 187(Volume 187) pp:
Publication Date(Web):1 February 2017
DOI:10.1016/j.apenergy.2016.11.043
•A hierarchical porous polymer (HPP) with high porosity (91.9%) was synthesized.•The HPP shows pressure-dependent elastic deformation behavior for ssPCMs.•The interaction in HPP induces the stability of the β phase of 1-octadecanol.•The HPP reduce the extent of the supercooling of 1-octadecanol (37%) effectively.•The ssPCMs have high adsorption of 1-octadecanol and high energy storage density.A hierarchical porous polymer (HPP), which was prepared by the imine condensation between pararosaniline base and 1,4-phthalaldehyde, has been used as the supporting material for novel shape-stability phase change materials (ssPCMs). With high porosity (91.9%), the hierarchical pores in the HPP supply sufficient space to adsorb 1-octadecanol, which is restricted in pores by the weak interactions such as hydrogen bonding, surface tension and capillary force in the interfacial region. The HPP exhibits high adsorption of 1-octadecanol (75 wt%) in the ssPCMs, the relative enthalpy of which is up to 169.2 J/g. The solid 13C NMR spectra and XRD results show that the hydrogen bonding interaction between 1-octadecanol and the HPP in the interfacial region increases the rotational and translational disorder of the 1-octadecanol, and induces the stability of the β phase, effectively reducing the extent of the supercooling of the 1-octadecanol (up to 37%). With its pressure-dependent elastic deformation behavior, the HPP can be adaptable along well with the phase transition of 1-octadecanol, which is of benefit to the crystallinities of 1-octadecanol and the shape stability of the composite PCMs. Thermal cycling and DSC results also confirm the high shape-stability and thermal stability of the ssPCMs.Schematic illustration of the prepared procedure of 1-octadecanol@HPP ssPCM.Download high-res image (100KB)Download full-size image
Co-reporter:Yi Luan, Ming Yang, Qianqian Ma, Yue Qi, Hongyi Gao, Zhenyu Wu and Ge Wang
Journal of Materials Chemistry A 2016 vol. 4(Issue 20) pp:7641-7649
Publication Date(Web):12 Apr 2016
DOI:10.1039/C6TA01676F
The design and synthesis of a shape-stabilized composite phase change material (PCM) is the most practical approach for addressing the leakage issue of phase change materials. This manuscript describes a facile solution impregnation method to access a novel type of shape-stabilized PCM employing metal–organic frameworks as the matrix. A fatty acid@metal–organic framework (MOF) composite PCM for low temperature heat storage has been developed for the first time. The metal–organic framework serves as an ideal host material for achieving a composite PCM taking advantage of its highly porous structure and tunable host–guest interactions. PXRD, FTIR, SEM, TGA, BET and DSC characterization studies have been conducted to reveal the structural and thermal properties of the newly achieved PCM composites. The results showed that one-step synthesized MIL-101-NH2 provided the most optimal thermal properties and the highest stearic acid mass percentage was achieved at 70 wt%, which corresponds to the highest loading and highest enthalpy in the literature for organic acid derived shape-stabilized PCMs. Furthermore, the thermal performance of the fatty acid@MOF composite PCM was maintained after 50 cycles, which indicates its great thermal stability.
Co-reporter:Jingjing Wang, Mu Yang, Wenjun Dong, Zhaokui Jin, Jia Tang, Shuang Fan, Yunfeng Lu and Ge Wang
Catalysis Science & Technology 2016 vol. 6(Issue 1) pp:161-168
Publication Date(Web):08 Oct 2015
DOI:10.1039/C5CY01099C
A series of efficient cobalt(II)-anchored Cr-MOF (Cr-MIL-101-NH2) catalysts, such as Co(II)@Cr-MIL-101-Sal, Co(II)@Cr-MIL-101-P2I and Co(II)@Cr-MIL-101-P3I, have been successfully synthesized by one-pot modification of the terminal amino group with salicylaldehyde, pyridine-2-aldehyde or pyridine-3-aldehyde and anchoring of Co(II) ions into the mesoporous Cr-MOF supports. The Co(II)@Cr-MIL-101-P2I catalyst exhibited high catalytic performance for epoxidation of olefins with air as an oxidant due to the nitrogen atom in the pyridine ring as a strong electron-withdrawing substituent, high dispersion of Co(II) species and high surface area for sufficient contact between the substrate and active sites. The strong coordination interaction between the Co(II) ions and chelating groups in the Co(II)@Cr-MIL-101-P2I catalyst guaranteed the excellent recycling performance. Furthermore, the synthesized Co(II)@Cr-MIL-101-P2I catalyst realized its general applicability towards various olefins, such as cyclic olefins, tri-substituted olefins, aliphatic olefins and aromatic olefins.
Co-reporter:Jia Tang, Ming Yang, Wenjun Dong, Mu Yang, Huan Zhang, Shuang Fan, Jun Wang, Li Tan and Ge Wang
RSC Advances 2016 vol. 6(Issue 46) pp:40106-40114
Publication Date(Web):05 Apr 2016
DOI:10.1039/C6RA04059D
Highly porous carbons (HPCs) are successfully prepared using a controlled carbonization of metal organic frameworks (MOFs) method. New micropores and mesoporous channels are produced during the migration and aggregation of small ZnO particles in the carbon matrix, while larger nanocavities are created after the evaporation of ZnO particles. The HPCs with high surface area (up to 2551 m2 g−1) and large total pore volume (up to 3.05 cm3 g−1) have high adsorption of polyethylene glycol (PEG) (up to 92.5 wt%) for shape-stabilized phase change materials (ssPCMs). In the PEG@HPCs composites, the nanocavities with a large mesopore volume guarantee the high storage of PEG molecules, and the micropores and mesoporous channels induced surface tension and capillary force to ensure the high thermal stability of the composites. With a high content of PEG and good shape-stabilities, the PEG@HPCs show high phase change enthalpy, which is close to or even higher than that of pure PEG. The thermal conductivity of PEG can also be improved by HPCs.
Co-reporter:Yinhai Tang, Mu Yang, Hongyi Gao, Jie Li, Ge Wang
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2016 Volume 508() pp:184-191
Publication Date(Web):5 November 2016
DOI:10.1016/j.colsurfa.2016.08.050
•A novel L-EISA approach for TiO2 hierarchical nanostructures is developed.•The self-assembly of P123 and growth TiO2 sol influence the constructure of TiO2.•Lyophilization retains the middle-structure and prevent the further growth of TiO2.•TiO2 hierarchical nanostructures exhibits excellent photocatalytic activity.In this paper, a novel lyophilizated evaporation-induced self-assembly (L-EISA) approach for morphology controllable TiO2 hierarchical nanostructures in pure water-based system was developed. The resulting TiO2 nanostructures were obtained by controlling the self-assembly and growth of the P123 and TiO2 sol complex. During the synthesis procedure, the aging temperature influences the self-assembled behavior of the template in the solution, the interaction between P123 and TiO2 sol particles, and the crystal growth of TiO2. At the aging temperature of 50 °C (P0.5-TiO2-50), TiO2 hierarchical nanostructure composed of radical array of nanoneedle and some adhered nanocrystallines were obtained. Lyophilization was employed to retain the structure and prevent the further growth of TiO2 crystalline during the drying process. After calcination, the structures were well preserved. P0.5-TiO2-50 possesses a relatively high surface area of ∼210.3 m2 g−1 and a large average pore size of ∼12.56 nm. With the high surface area, crystalline and specific nanostructure, P0.5-TiO2-50 exhibits excellent photocatalytic activity on the degradation of RhB under solar-light.
Co-reporter:Jingjing Wang, Mu Yang, Yunfeng Lu, Zhaokui Jin, Li Tan, Hongyi Gao, Shuang Fan, Wenjun Dong, Ge Wang
Nano Energy 2016 Volume 19() pp:78-87
Publication Date(Web):January 2016
DOI:10.1016/j.nanoen.2015.11.001
•The surface functionalization engineering of SBA-15 was developed.•The internal amino groups changed the adsorption conformation of PEG chains.•The external methyl groups restrained the spillover of PEG molecules.•The fusion enthalpy of PEG/SBA-15 composite was adjusted from 0 J/g to 88.2 J/g.Crystallization behaviors of organic phase change materials (PCMs) confined in porous supports, which are determined by the interactions between PCM molecules and channel surface of the supports, are a prerequisite for the storage and release of latent heat in PCMs. In this work, surface functionalization was engineered to regulate the interactions between a PCM of polyethylene glycol (PEG) and internal/external surfaces of a support of SBA-15 and the crystallization/stabilization behavior of PEG, and yield desirable thermal properties of the PEG confined in SBA-15 channels. To investigate the effect of the internal/external surfaces of SBA-15 on the crystallization/stabilization behavior of PEG, SBA-15 supports were modified with various functional terminals, such as NH2-SBA-15-NH2 and NH2-SBA-15-CH3. The fusion enthalpy was increased from 0 J/g of PEG/HO-SBA-15-OH composite to 88.2 J/g of PEG/NH2-SBA-15-CH3 composite. The amino groups modified on the internal surface of SBA-15 reduced the hydrogen bond interactions between PCM molecules and the channel surface of the supports, and also altered the adsorption conformation of the PEG chains from train structure to loop structure, which is conducive to the stretching and crystallization of the PEG chains. Further, the methyl groups grafted on the external surface of SBA-15 restrained the spillover of PEG molecules from the channels due to the opposite polarities of PEG molecules and methyl groups. Crystallization behavior of the PEG molecules in channels of SBA-15 driven by surface functionalization engineering yields a controllable phase change enthalpy of PEG/SBA-15 composite and provides a general approach for the controlling of the thermal properties of PCMs.The amino functionalization engineering on the internal surface of SBA-15 decreased the amount of adsorption sites of PEG chains, as well as changing the adsorption conformation of PEG chains from the train structure to the loop structure. The methyl functionalization engineering on the external surface of SBA-15 restrained the spillover of PEG molecules from the channels. Under driven crystallization behavior of polyethylene glycol by surface functionalization engineering, the fusion enthalpy was increased from 0 J/g of PEG/HO-SBA-15-OH composite to 88.2 J/g of PEG/NH2-SBA-15-CH3 composite.
Co-reporter:Xiaowei Zhang, Wenjun Dong, Yi Luan, Mu Yang, Li Tan, Yangguang Guo, Hongyi Gao, Yinhai Tang, Rui Dang, Jie Li and Ge Wang
Journal of Materials Chemistry A 2015 vol. 3(Issue 8) pp:4266-4273
Publication Date(Web):08 Jan 2015
DOI:10.1039/C4TA06046F
A novel catalyst consisting of a functional sulfonated-polystyrene (SPS) core, a porous Cu3(BTC)2 shell and an active Cu(II) interface between the core and shell was developed via a facile step-by-step assembly method. The polystyrene core was sulfonated first to achieve functional –SO3H groups on its surface. The main function of the –SO3H groups was to graft Cu(II) ions to generate an active Cu(II) interface, and the excess –SO3H could provide acid conditions for the catalytic reaction. The Cu(II) interface along with the acid conditions and the co-catalyst 2,2,6,6-tetramethyl-piperidyl-1-oxy (TEMPO) enhanced the catalytic activity for the aerobic oxidation of alcohols to aldehydes by molecular oxygen under base-free conditions. A portion of Cu(II) ions on the SPS surface was then coordinated with H3BTC (1,3,5-benzenetricarboxylic acid) to form a porous Cu3(BTC)2 shell, which could protect the active metal from leaching as well as provide porous channels for mass transfer, resulting in high stability and recyclability in the catalysis procedure. The SPS–Cu(II)@Cu3(BTC)2 catalyst could be recycled ten times without a significant loss in its activity and selectivity. Furthermore, the SPS–Cu(II)@CuBDC (BDC = 1,4-benzenedicarboxylate) composite was also synthesized and showed high efficiency for catalyzing the aerobic oxidation of alcohols and aerobic homocoupling of arylboronic acids, suggesting that the unique nanostructure of SPS–Cu(II)@MOFs can be easily extended to design complex catalysts with high efficiency and good stability for different catalytic reactions.
Co-reporter:Yi Luan, Yue Qi, Hongyi Gao, Radoelizo S. Andriamitantsoa, Nannan Zheng and Ge Wang
Journal of Materials Chemistry A 2015 vol. 3(Issue 33) pp:17320-17331
Publication Date(Web):08 Jul 2015
DOI:10.1039/C5TA00816F
In this manuscript, four common transition-metal derived metal–organic frameworks have been extensively investigated as heterogeneous catalyst supports for Knoevenagel condensation reactions. A simple post-synthetic modification strategy was employed for the rapid and facile introduction of a primary alkyl amino group. The resulting novel MOF–RNH2 catalysts showed greatly enhanced Knoevenagel condensation reactivities towards a variety of aldehyde electrophiles. IRMOF-3 proved to be an unsuitable heterogeneous catalyst support due to its fragile nature upon treatment with bases. The novel zirconium based UiO-66–NH–RNH2 and chromium based Cr-MIL-101–NH–RNH2 materials showed excellent catalytic reactivities, while being highly convenient to synthesize. The basic catalytic activity was further extended to the Henry reaction, and excellent catalytic reactivity was achieved. The size-selectivity was also studied to show that the Knoevenagel condensation occurred inside of the porous structure of the MOF catalyst. The recycling properties of zirconium, aluminum and chromium derived MOFs were evaluated and zirconium based UiO-66 and chromium based Cr-MIL-101 showed excellent catalytic efficiency after five reaction cycles.
Co-reporter:Hongyi Gao, Yi Luan, Kullapat Chaikittikul, Wenjun Dong, Jie Li, Xiaowei Zhang, Dandan Jia, Mu Yang, and Ge Wang
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 8) pp:4667
Publication Date(Web):February 13, 2015
DOI:10.1021/am508079j
A hierarchical yolk/shell copper hydroxysulfates@MOF (CHS@MOF, where MOF = metal–organic frameworks) structure was fabricated from a homogeneous yolk/shell CHS template composed of an active shell and a stabilized core via a facile self-template strategy at room temperature. The active shell of the template served as the source of metal ion and was in situ transformed into a well-defined MOF crystal shell, and the relatively stabilized core retained its own nature during the formation of the MOF shell. The strategy of in situ transformation of CHS shell to MOF shell avoided the self-nucleation of MOF in the solution and complex multistep procedures. Furthermore, a flow reaction system using CHS@MOF as self-supported stationary-phase catalyst was developed, which demonstrated excellent catalytic performance for aldehyde acetalization with ethanol, and high yields and selectivities were achieved under mild conditions.Keywords: CHS@MOF; in situ transformation; self-template; yolk/shell
Co-reporter:Jie Li, Zeting Huang, Mu Yang, Li Tan, Xiaowei Zhang, Hongyi Gao, Yinhai Tang, Qianqian Ma and Ge Wang
New Journal of Chemistry 2015 vol. 39(Issue 4) pp:2949-2955
Publication Date(Web):05 Feb 2015
DOI:10.1039/C4NJ02112F
Core–shell C@poly(4-vinylpyridine) (C@P4VP) microspheres immobilized with small and uniform Au nanoparticles were designed and fabricated. Firstly, the C@P4VP support was obtained by coating a poly(4-vinylpyridine) shell on the carbon spheres through the hydrogen-bond interaction between –COOH of carbon spheres and pyridine of 4-vinylpyridine. Then Au nanoparticles were synthesized by in situ adsorption and reduction of HAuCl4 in the P4VP chains of the C@P4VP microspheres. Carbon spheres can serve as hard templates and prevent the polymeric P4VP shell from excessive deformation. The coordination between cross-linked networks of P4VP chains and the embedded Au nanoparticles effectively inhibit the aggregation and leaching of noble metal nanoparticles from the support. The resulting C@P4VP–Au microspheres showed excellent catalytic performance and high cyclic stability in the aqueous reduction of 4-nitrophenol by NaBH4. Moreover, optimal activities were observed for the P4VP shell with a low cross-linked degree and a reaction system with a low pH value.
Co-reporter:Yi Luan, Yue Qi, Zhaokui Jin, Xiong Peng, Hongyi Gao and Ge Wang
RSC Advances 2015 vol. 5(Issue 25) pp:19273-19278
Publication Date(Web):09 Feb 2015
DOI:10.1039/C4RA15257C
The synthesis of metal–organic frameworks with Brønsted acid moieties is usually tedious and the study of metal–organic frameworks as a heterogeneous Brønsted acid catalyst is limited. In this manuscript, a facile one-step synthesis of UiO-66-(COOH)2 material with a flower-like morphology has been developed. The as-synthesized flower-like UiO-66-(COOH)2 can serve as an efficient Brønsted acid in nitro-Mannich and Mannich reactions taking advantage of its morphology assembled from nanoscaled plates. 72–99% yields of Mannich adducts were obtained for a variety of acyl imine substrates in the presence of 0.5 mol% MOF catalyst under extremely mild conditions. Furthermore, the as-synthesized flower-like UiO-66-(COOH)2 catalyst can be recycled several times without compromising the catalytic activity.
Co-reporter:Yue Qi;Yi Luan;Xiong Peng;Ming Yang;Junying Hou
European Journal of Inorganic Chemistry 2015 Volume 2015( Issue 30) pp:5099-5105
Publication Date(Web):
DOI:10.1002/ejic.201500808
Abstract
Highly dispersed gold nanoparticles were deposited on an amino-functionalized Al-based MIL-53 metal–organic framework by a facile adsorption/reduction strategy. The aromatic amino groups were utilized for adsorption and stabilization of AuCl4– and as basic catalytic sites in the Knoevenagel reaction. The bifunctional Au@MIL-53(NH2) catalyst was utilized to develop an efficient one-pot aerobic oxidation of alcohols/Knoevenagel condensation reaction that takes advantage of Au0 and NH2 incorporation at the same time. The roles of Au and NH2 groups were systematically investigated to elucidate their functionality during the one-pot reaction. In addition, the Au@MIL-53(NH2) catalyst can be easily recycled up to five times without leaching of the active centres or significant loss of catalytic activity.
Co-reporter:Xiubing Huang, Guixia Zhao, Ge Wang, Yinhai Tang, Zhan Shi
Microporous and Mesoporous Materials 2015 Volume 207() pp:105-110
Publication Date(Web):1 May 2015
DOI:10.1016/j.micromeso.2015.01.008
•Effect of metal species on morphology was investigated via a double-solvent method.•Different metal nitrate species lead to different morphologies.•The growth nature and confinement of mesoporous co-affect their morphology.In this work, several kinds of nanostructured metal (Ag nanowires) or metal oxides (MnOx nanowires, Co3O4 nanoparticles, NiO nanoparticles, CuO nanoparticles) within the mesochannels of SBA-15 have been synthesized by a double-solvent method, in which n-hexane was used as a hydrophobic solvent and metal nitrate aqueous solution as a hydrophilic solvent. The influence of metal nitrate precursor species and concentration on the loading and morphology of metal (oxides) within the mesochannels of SBA-15 was investigated. XRD, N2 adsorption/desorption isotherms and HRTEM were used to characterize these composite materials. It is found that the growth nature of metal (oxides) as well as the confinement effect of mesoporous have great influence on their morphology within the mesochannels of SBA-15. These results in this research would give some instructive information for the morphology design of metal (oxide) with the use of nanoporous template.
Co-reporter:Yinhai Tang, Mu Yang, Wenjun Dong, Li Tan, Xiaowei Zhang, Peng Zhao, Chaohao Peng, Ge Wang
Microporous and Mesoporous Materials 2015 Volume 215() pp:199-205
Publication Date(Web):1 October 2015
DOI:10.1016/j.micromeso.2015.05.040
•A novel temperature difference effect induced self-assembly method for Ag/SBA-15.•The precursor was pushed into the channels by temperature difference effect.•Ag nanoparticles, nanorods and nanowires/SBA-15 are obtained.•The weight ratio of AgNO3/SBA-15 influences the morphology of Ag/SBA-15.In this paper the first dynamics-controlled self-assembly method for Ag nanostructures in mesoporous channels is developed, and Ag/SBA-15 nanostructures are synthesized by a temperature difference effect induced self-assembly method with AgNO3 as Ag precursor and SBA-15 as support. Different morphologies of Ag nanomaterials such as nanoparticles, nanorods, and nanowires can be controlled by changing the weight ratio of AgNO3/SBA-15. In the synthesis procedure, the temperature difference effect induces air volume shrinkage in the channel, and the drop in pressure pushes the molten AgNO3 assembled into the channels step by step. Finally, Ag/SBA-15 nanostructures are obtained by calcination at 350 °C for 2 h. Furthermore, the catalytic activities of Ag/SBA-15 nanostructures toward the epoxidation of styrene are investigated, and Ag nanoparticles/SBA-15-130 shows 77.7% of conversion and 73.7% selectivity for the epoxidation of styrene.
Co-reporter:Yue Qi;Dr. Yi Luan;Jie Yu;Xiong Peng ;Dr. Ge Wang
Chemistry - A European Journal 2015 Volume 21( Issue 4) pp:1589-1597
Publication Date(Web):
DOI:10.1002/chem.201405685
Abstract
Aerobic epoxidation of olefins at a mild reaction temperature has been carried out by using nanomorphology of [Cu3(BTC)2] (BTC=1,3,5-benzenetricarboxylate) as a high-performance catalyst through a simple synthetic strategy. An aromatic carboxylate ligand was employed to furnish a heterogeneous copper catalyst and also serves as the ligand for enhanced catalytic activities in the catalytic reaction. The utilization of a copper metal–organic framework catalyst was further extended to the aerobic oxidation of aromatic alcohols. The shape and size selectivity of the catalyst in olefin epoxidation and alcohol oxidation was investigated. Furthermore, the as-synthesized copper catalyst can be easily recovered and reused several times without leaching of active species or significant loss of activity.
Co-reporter:Wanchun Guo;Qian Wang;Yi Luan; Ge Wang; Wenjun Dong;Jie Yu
Chemistry – An Asian Journal 2015 Volume 10( Issue 3) pp:701-708
Publication Date(Web):
DOI:10.1002/asia.201403251
Abstract
Hierarchical Fe3O4@SiO2@P(4VP-DVB)@Au nanostructures were prepared in which the slightly cross-linked, thin poly(4-vinylpyridine-co-divinylbenzene) (P(4VP-DVB)) shells were constructed onto Fe3O4@SiO2 nanospheres, followed by in situ embedding of gold nanocrystals homogeneously into the P4VP chains. These slightly cross-linked chains, easily swollen by the reactants, make the gold nanocrystals accessible to the reactants, and the thin shell (about 15 nm) reduces the diffusion distance of the reactants to the active gold nanocrystals (about 5 nm), thereby enhancing their catalytic activity and utility. At the same time, confinement of gold nanocrystals within the P4VP shells prevents their migration and coagulation during catalytic transformations. Hence the nanocomposites exhibit high activity (up to 4369.5 h−1 of turnover frequency (TOF)) and controllable magnetic recyclability without any significant loss of gold species after ten runs of catalysis in the reduction of 4-nitrophenol.
Co-reporter:Chao Lei, Zheng Chen, Hiesang Sohn, Xiaolei Wang, Zaiyuan Le, Ding Weng, Meiqing Shen, Ge Wang and Yunfeng Lu
Journal of Materials Chemistry A 2014 vol. 2(Issue 41) pp:17536-17544
Publication Date(Web):09 Sep 2014
DOI:10.1039/C4TA03715D
Lithium-ion storage materials with significantly improved performance were developed through the hierarchical assemblies of vanadium-based oxide (V2O5 and LiV3O8) nanorods or iron oxide (Fe3O4) nanocrystals using an efficient, continuous aerosol-spray process. Such hierarchically porous spheres, which were made from networks of low-dimension building blocks, result in materials with reduced ion-diffusion length, fast electrolyte diffusion, and structural robustness. Due to their unique hierarchical structure, these spheres exhibit high lithium storage capacity, excellent cycling stability and good rate capability. This work presents a novel synthesis approach toward better lithium-ion storage materials.
Co-reporter:Yi Luan, Yue Qi, Hongyi Gao, Nannan Zheng and Ge Wang
Journal of Materials Chemistry A 2014 vol. 2(Issue 48) pp:20588-20596
Publication Date(Web):08 Sep 2014
DOI:10.1039/C4TA04311A
In this study, highly dispersed Au nanoparticles have been immobilized on amino-functionalized metal–organic frameworks (MOFs) via a novel absorption/reduction method in solution. The amino functionality of the MOF rapidly coordinated with HAuCl4 and acted as the Au(0) precursor in the absence of protecting agents. The resulting Au@MOF catalyst was well dispersed in aqueous media taking advantage of its well-defined and uniform sizes and nanomorphologies. The as-synthesized Au@MOF catalyst exhibited high catalytic activities in a wide variety of reactions under ambient conditions, such as the base-free aerobic oxidation of alcohols and oxidation/imine formation/reduction reaction sequences. Furthermore, the Au@MOF catalyst can be easily recovered and reused several times without leaching of metals or significant loss of activity.
Co-reporter:Rui Dang, Lingling Song, Wenjun Dong, Chaorong Li, Xiaobo Zhang, Ge Wang, and Xiaobo Chen
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 1) pp:622
Publication Date(Web):December 6, 2013
DOI:10.1021/am404708z
Large-area Cu nanosheets are synthesized by a strategy of Cu nanocrystal self-assembly, and then aqueous conductive Cu nanosheet ink is successfully prepared for direct writing on the conductive circuits of flexible electronics. The Cu nanocrystals, as building blocks, self-assemble along the ⟨111⟩ direction and grow into large-area nanosheets approximately 30–100 μm in diameter and a few hundred nanometers in thickness. The laminar stackable patterns of the Cu nanosheet circuits increase the contact area of the Cu nanosheets and improve the stability of the conductor under stress, the result being that the Cu nanosheet circuits display excellent conductive performance during repeated folding and unfolding. Moreover, heterostructures of Ag nanoparticle-coated Cu nanosheets are created to improve the thermal stability of the nanosheet circuits at high temperatures.Keywords: conductive ink; Cu nanosheets; flexible electronics; nanomaterials; self-assembly;
Co-reporter:Yi Luan, Nannan Zheng, Yue Qi, Jia Tang and Ge Wang
Catalysis Science & Technology 2014 vol. 4(Issue 4) pp:925-929
Publication Date(Web):06 Jan 2014
DOI:10.1039/C3CY00864A
A new thiourea-containing metal–organic framework (MOF) catalyst was synthesized. It overcomes recycling, self-aggregation and solvation issues that exist in homogeneous thiourea catalysts. Nanomorphology was introduced to increase the dispersion of the solid catalyst in solvent. Acetalization and Morita–Baylis–Hillman reactions were catalyzed using the new thiourea MOF catalyst.
Co-reporter:Xiaowei Zhang, Ge Wang, Mu Yang, Yi Luan, Wenjun Dong, Rui Dang, Hongyi Gao and Jie Yu
Catalysis Science & Technology 2014 vol. 4(Issue 9) pp:3082-3089
Publication Date(Web):09 May 2014
DOI:10.1039/C4CY00430B
A novel hybrid Fe3O4–CuO@meso-SiO2 catalyst was successfully fabricated by a multi-step assembly method. CuO nanoparticles were first deposited on the surface of Fe3O4 microspheres to form the Fe3O4–CuO hybrid microspheres through a solvothermal reaction. A mesoporous silica (meso-SiO2) shell, with perpendicularly aligned pore channels, was then coated on the hybrid microspheres using sol–gel technology. The Fe3O4 microspheres not only offered fast and effective recycling properties for the catalyst but also acted as electron donors to CuO, leading to a higher electron density on the CuO surface and a subsequently enhanced catalytic performance. The mesoporous silica shell provided strong protection against the aggregation and leaking of the active CuO nanoparticles and also offered appropriate channels for an efficient mass transfer of the catalytic reaction. The Fe3O4–CuO@meso-SiO2 catalyst exhibited excellent activity, convenient magnetic separability and good stability in the catalytic epoxidation of styrene.
Co-reporter:Hongyi Gao, Ge Wang, Yi Luan, Kullapat Chaikittikul, Xiaowei Zhang, Mu Yang, Wenjun Dong and Zhan Shi
CrystEngComm 2014 vol. 16(Issue 12) pp:2520-2526
Publication Date(Web):17 Jan 2014
DOI:10.1039/C3CE42256A
Hierarchical 3D yolk–shell copper hydroxysulfate microspheres were successfully synthesized by a fast synthesis method at room temperature. Both the core and the shell of the yolk–shell microspheres were assembled from 2D nanoplates or tiny nanoplatelets. The as-synthesized products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectrometry (XPS), atomic absorption spectrophotometry (AAS) and thermogravimetric analysis (TG). The diameter of the yolk–shell microspheres can be tuned by simply adjusting the concentration of the chelating agent, 1,3-propanediamine. This reaction can be scaled up by a factor of 1000 with almost no loss in yield. An Ostwald ripening controlled formation mechanism was proposed. Furthermore, the yolk–shell copper hydroxysulfates were evaluated as catalysts for the oxidation of styrene to benzaldehyde.
Co-reporter:Limin Zhong, Xiaowei Zhang, Yi Luan, Ge Wang, Yanhui Feng, Daili Feng
Solar Energy 2014 Volume 107() pp:63-73
Publication Date(Web):September 2014
DOI:10.1016/j.solener.2014.05.019
•Molten salts/expanded graphite composite phase change materials were prepared.•The content of molten salts in the composites was from 77.8% to 81.5%.•Thermal conductivity of molten salts was enhanced after impregnation with EG.•Composites showed great thermal stability after 40 cycles.•Composites were designed for future use in cascaded latent heat storage.Three kinds of porous heterogeneous composite phase change materials were synthesized from expanded graphite (EG) and binary molten salts (LiNO3–KCl, LiNO3–NaNO3 and LiNO3–NaCl) through solution impregnation method. Binary molten salt content in the composite phase change materials was calculated to be between 77.8% and 81.5% and high encapsulation efficiency was calculated to be between 72.8% and 78.8%. The thermal conductivity of binary molten salts was enhanced by 4.9–6.9 times after impregnation with EG. SEM photographs showed that the prepared composites were more homogeneous in comparison to other salt/EG composites prepared by infiltration or compression. Phase change properties of the porous heterogeneous composite phase change materials showed great thermal stability, which was maintained after 100 cycles.
Co-reporter:Xi Tan, Hongyi Gao, Mu Yang, Yi Luan, Wenjun Dong, Zhaokui Jin, Jie Yu, Yue Qi, Yanhui Feng, Ge Wang
Journal of Alloys and Compounds 2014 Volume 608() pp:278-282
Publication Date(Web):25 September 2014
DOI:10.1016/j.jallcom.2014.04.042
•Three-dimensional sisal-shaped β-cobalt hydroxide and oxide are synthesized.•The products are assembled from building blocks with the shape of tower of Hanoi.•The morphologies, structures and sizes of products could be easily controlled.•The products exhibited promising electrochemical applications.Sisal-shaped hierarchical cobalt hydroxide was obtained by a simple hydrothermal method, and cobalt oxide was also easily obtained by heating the cobalt hydroxide in air. The obtained cobalt oxide possessed a similar hierarchical structure to the cobalt hydroxide. The prepared cobalt hydroxide samples were made of building blocks which took the shape of tower of Hanoi. The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR), field scanning electron microscope (FESEM), high resolution transmission electron microscopy (HRTEM) and thermogravimetry analysis (TG), which implied that various morphologies and structures of the samples could be easily obtained by changing the molar ratio of cobalt nitrate to TETA, the amount of sodium hydroxide added and reaction temperature. Furthermore, the formation mechanisms were explained. Finally, the electrochemical properties were evaluated and the prepared samples exhibited promising electrochemical applications.Graphical abstractSisal-shaped hierarchical cobalt hydroxide was obtained by a simple hydrothermal method, and cobalt oxide was also easily obtained by heating the cobalt hydroxide in air. The obtained cobalt oxide possessed a similar hierarchical structure to the cobalt hydroxide. The prepared cobalt hydroxide samples were made of building blocks which took the shape of tower of Hanoi. The prepared samples exhibited promising electrochemical applications.
Co-reporter:Yi Luan;Nannan Zheng;Yue Qi;Jie Yu
European Journal of Inorganic Chemistry 2014 Volume 2014( Issue 26) pp:4268-4272
Publication Date(Web):
DOI:10.1002/ejic.201402509
Abstract
A novel metal–organic framework UiO-66-NH2-derived Brønsted acid catalyst was synthesized on a gram scale by employing a postsynthetic modification strategy under mild conditions. The nanomorphology of the catalyst was designed and developed to enhance its catalytic performance. Acetalization and benzimidazole formation were evaluated to demonstrate the high reactivity and selectivity of the nanoscaled UiO-66-NH-RSO3H catalyst, which were found to be comparable to the reactivity and selectivity of the strong homogeneous Brønsted acid catalyst. Furthermore, the UiO-66-NH-RSO3H catalyst was recycled several times without compromising the yield and selectivity.
Co-reporter:Jia Tang, Wenjun Dong, Ge Wang, Yuze Yao, Leiming Cai, Yi Liu, Xuan Zhao, Jingqi Xu and Li Tan
RSC Advances 2014 vol. 4(Issue 81) pp:42977-42982
Publication Date(Web):19 Aug 2014
DOI:10.1039/C4RA07133F
Efficient molybdenum(VI) modified Zr-MOF catalysts have been successfully prepared for the epoxidation of olefins. The stable and porous Zr-MOF (UiO-66(NH2)) was modified with salicylaldehyde, pyridine-2-aldehyde, or 2-pyridine chloride by the post-synthesis modification (PSM) method, and then the Mo-based catalyst was loaded by a chelating method. The MOFs not only act as the carriers of the Mo(VI) catalyst, but also improve the contacting ability between the substrate and the active center of the Mo(VI) compound. The high dispersion of the Mo catalyst on Zr-MOF and the big pore size of MOF guarantee sufficient contact between substrate and catalytic active center, thus accelerating the rate of reaction and providing improved catalytic efficiency for the epoxidation of olefins. The obtained Zr-MOF catalyst exhibited high activity for the epoxidation of olefins with 70 wt% tert-butyl hydroperoxide (TBHP) or 30% H2O2 as the oxygen sources. Furthermore, MoO2(acac)2 loaded Zr-MOF was prepared in the same way, and it also showed good catalytic performance for the epoxidation of olefins.
Co-reporter:Jie Yu, Yi Luan, Yue Qi, Junying Hou, Wenjun Dong, Mu Yang and Ge Wang
RSC Advances 2014 vol. 4(Issue 98) pp:55028-55035
Publication Date(Web):07 Oct 2014
DOI:10.1039/C4RA06944G
Hierarchical heterogeneous copper catalysts were prepared by immobilization of a homogeneous copper(II) complex on the surface of polystyrene/polyaniline (PS/PANI) microspheres with oriented PANI nanofibers. EDX element maps and XPS spectra indicated that Cu2+ ions strongly coordinated with PANI imine. PS/PANI@Cu(OSO2CF3)2 exhibited excellent catalytic activity for selective aerobic oxidation of alcohols and highly efficient aerobic epoxidation of alkenes under mild conditions. The supported copper(II) catalyst maintained high levels of conversion and selectivity in these reactions after six cycles and showed good stability.
Co-reporter:Yi Luan, Jie Yu, Xiaowei Zhang, Scott E. Schaus, and Ge Wang
The Journal of Organic Chemistry 2014 Volume 79(Issue 10) pp:4694-4698
Publication Date(Web):April 30, 2014
DOI:10.1021/jo5003505
Diazo compounds, boranes, and acyl imines undergo a three-component Mannich condensation reaction under catalyst-free conditions to give the anti β-amino carbonyl compounds in high diastereoselectivity. The reaction tolerates a variety of functional groups, and an asymmetric variant was achieved using the (−)-phenylmenthol as chiral auxiliary in good yield and selectivity. These β-amino carbonyl compounds are valuable intermediates, which can be transformed to many potential bioactive molecules.
Co-reporter:Mu Yang, Yangguang Guo, Qiang Wu, Yi Luan, Ge Wang
Polymer 2014 Volume 55(Issue 8) pp:1948-1954
Publication Date(Web):10 April 2014
DOI:10.1016/j.polymer.2014.02.064
Amphiphilic nonspherical particles have asymmetric surface physical and chemical properties. Such a unique structure makes them suitable for applications in many areas, such as chemical and biological sensors, colloidal surfactants, self-assembly, building blocks of complex superstructures, and materials engineering. In this study, amphiphilic sulfonated polystyrene/polystyrene (SPS/PS) composite particles with controllable morphologies are synthesized by combining modified treatment and multistage seeded swelling polymerization. Core-shell SPS particles were first obtained by modifying cross-linked PS particles with concentrated sulfuric acid, and the surface of SPS particles was a hydrophilic sulfonated polystyrene layer. With further twice seeded swelling polymerization, new hydrophobic PS oil phase sprouted on the strong hydrophilic surface even without any surfactant assistance in aqueous media. The morphologies of these SPS/PS composite particles could be adjusted by changing the crosslinking density of the seed microspheres, the sulfonation temperature and the swelling ratio of monomer/seed. These polymer composite particles can be used as solid surfactants.
Co-reporter:Xiaowei Zhang, Ni Huang, Ge Wang, Wenjun Dong, Mu Yang, Yi Luan, Zhan Shi
Microporous and Mesoporous Materials 2013 Volume 177() pp:47-53
Publication Date(Web):1 September 2013
DOI:10.1016/j.micromeso.2013.04.012
•A novel ultrasonic post-grafting method has been developed.•A reusable CuO/SBA-15 catalyst with high copper loading and good dispersion has been synthesized and characterized.•Direct hydroxylation of benzene to phenol has been carried out with the CuO/SBA-15 catalyst.•The obtained catalyst exhibits high catalytic activity and recyclability.A novel ultrasonic post-grafting method has been developed to obtain highly-loaded and well-dispersed CuO nanoclusters inside the channels of mesoporous silica (SBA-15). Trimethylchlorosilane (TMCS) and 3-aminopropyltriethoxysilane (APTES) were used as modification surfactants, and copper nitrate solution was used as the precursor. The samples were characterized by FT-IR, XRD, SAXRD, ICP-AES, BET, HRTEM, TPR and XPS, which illustrated that the CuO clusters were well-dispersed in very small sizes. The hydroxylation of benzene to phenol in a one-step liquid-phase process using CuO/SBA-15 as the catalyst was evaluated. High conversion (28%) and selectivity (95%) were achieved with a 13.4 wt.% copper grafted on SBA-15. Furthermore, the catalyst was shown to have the ability to be recycled up to five times without a significant loss of conversion or selectivity.
Co-reporter:Hongyi Gao, Ge Wang, Mu Yang, Xiaowei Zhang, Zhan Shi, Chunguang Li, Xinxin Zhang and Xin Cui
RSC Advances 2013 vol. 3(Issue 8) pp:2604-2612
Publication Date(Web):07 Dec 2012
DOI:10.1039/C2RA22354F
In this work, Ni-incorporated β-Co(OH)2 with a novel well-ordered hierarchical double-faced brush structure assembled by a center round disk and two perpendicular nanorod arrays was successfully fabricated via a facial, template-free hydrothermal process in the presence of EDA. The brush length could be tuned by adjusting the Ni/Co molar ratio R. The as-synthesized products were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TG). The influence of the EDA addition, reacting temperature and reaction time on the formation of the hierarchical Ni-incorporated β-Co(OH)2 was investigated. A formation mechanism was proposed. The hierarchical Ni-incorporated β-Co(OH)2 was converted to Ni-incorporated Co3O4 by calcination successfully preserving the double-faced brush structure.
Co-reporter:Tianyu Bai;Feifei Li;He Huang;Zhaorui Wang;Zhan Shi;Chunguang Li;Shouhua Feng
European Journal of Inorganic Chemistry 2013 Volume 2013( Issue 34) pp:5906-5910
Publication Date(Web):
DOI:10.1002/ejic.201301069
Abstract
The morphology of CuInSe2 nanocrystals plays a key role in their functional properties. Achieving controllable morphology is significant for studying their structures and novel properties. Here, CuInSe2 nanocrystals with a trigonal-pyramidal shape have successfully been synthesized by a facile solution-phase method. The nanocrystals were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS), etc. The morphological evolution of the CuInSe2 nanocrystals was illustrated by tuning the injection temperature of oleylamine-selenium (OAm-Se). In addition, CuInSe2 nanocrystals with spherical and ellipsoidal shapes were also obtained when copper stearate was used as the copper precursor.
Co-reporter:Wanchun Guo;Qian Wang; Ge Wang;Mu Yang; Wenjun Dong;Jie Yu
Chemistry – An Asian Journal 2013 Volume 8( Issue 6) pp:
Publication Date(Web):
DOI:10.1002/asia.201390016
Co-reporter:Wanchun Guo;Qian Wang; Ge Wang;Mu Yang; Wenjun Dong;Jie Yu
Chemistry – An Asian Journal 2013 Volume 8( Issue 6) pp:1160-1167
Publication Date(Web):
DOI:10.1002/asia.201201186
Abstract
Hierarchical Fe3O4@poly(4-vinylpyridine-co-divinylbenzene)@Au (Fe3O4@P(4-VP–DVB)@Au) nanostructures were fabricated successfully by means of a facile two-step synthesis process. In this study, well-defined core–shell Fe3O4@P(4-VP–DVB) microspheres were first prepared with a simple polymerization method, in which 4-VP was easily polymerized on the surface of Fe3O4 nanoparticles by means of strong hydrogen-bond interactions between COOH groups on poly(acrylic acid)-modified Fe3O4 nanoparticles and a 4-VP monomer. HAuCl4 was adsorbed on the chains of a P(4-VP) shell and then reduced to Au nanoparticles by NaBH4, which were embedded into the P(4-VP) shell of the composite microspheres to finally form the Fe3O4@P(4-VP–DVB)@Au nanostructures. The obtained Fe3O4@P(4-VP–DVB)@Au catalysts with different Au loadings were applied in the reduction of 4-nitrophenol (4-NP) and exhibited excellent catalytic activity (up to 3025 h−1 of turnover frequency), facile magnetic separation (up to 31.9 emu g−1 of specific saturation magnetization), and good durability (over 98 % of conversion of 4-NP after ten runs of recyclable catalysis and almost negligible leaching of Au).
Co-reporter:Wanchun Guo, Ge Wang, Qian Wang, Wenjun Dong, Mu Yang, Xiubing Huang, Jie Yu, Zhan Shi
Journal of Molecular Catalysis A: Chemical 2013 Volume 378() pp:344-349
Publication Date(Web):1 November 2013
DOI:10.1016/j.molcata.2013.04.019
•Synthesis of novel Fe3O4/P4VP nanospheres via an miniemulsion polymerization.•Composite nanospheres with multiple Fe3O4 cores embedded in P4VP shell.•High catalytic efficiency of Fe3O4@P4VP@MoO2(acac)2 for the green epoxidation.•Facile magnetic recyclability of Fe3O4@P4VP@MoO2(acac)2 nanocatalyst.Magnetite/poly(4-vinylpyridine) composite nanospheres with multiple Fe3O4 cores embedded in a P4VP shell were first synthesized by miniemulsion polymerization and then used as recoverable supports for MoO2(acac)2 complex. The supported complex, together with superparamagnetism and strong magnetic response, showed high efficiency for the catalytic epoxidation of cis-cyclooctene with aqueous H2O2 in ethanol. The response strongly facilitated the easy recovery of the catalyst, which was stable in recycling tests.
Co-reporter:Zheng Chen, Ding Weng, Xiaolei Wang, Yanhua Cheng, Ge Wang and Yunfeng Lu
Chemical Communications 2012 vol. 48(Issue 31) pp:3736-3738
Publication Date(Web):01 Mar 2012
DOI:10.1039/C2CC30406F
Thin-film pseudocapacitor electrodes with ultrafast lithium storage kinetics, high capacitance and excellent cycling stability were fabricated from monodispersed TiO2 building nanocrystals, providing a novel approach towards next-generation micro-supercapacitor applications.
Co-reporter:Wenjun Dong, Xiaoyun Li, Jie Yu, Wanchun Guo, Bingjie Li, Li Tan, Chaorong Li, Jianjun Shi, Ge Wang
Materials Letters 2012 Volume 67(Issue 1) pp:131-134
Publication Date(Web):15 January 2012
DOI:10.1016/j.matlet.2011.09.045
Porous SrTiO3 spheres were successfully synthesized by a convenient hydrothermal method, employing SrCl2 as Sr source and titanate nanotube as Ti precursor. In this reaction, when short titanate nanotube was used as Ti precursor, porous SrTiO3 spheres were generated for the aggregation of the nanotube@SrTiO3 heteronanostructure. Whereas long titanate nanowire was used as the Ti precursor, solid SrTiO3 spheres were obtained due to the SrTiO3 which grows up gradually on the titanate nanowire. The morphology and the pore size of the SrTiO3 sphere structures can be easily controlled by simply adjusting the reaction time, reaction temperature and the Ti precursor. The porous SrTiO3 spheres exhibited enhanced photocatalytic activity which could achieve 100% degradation of Rhodamine B with a UV irradiation for 20 min.Highlights► Porous SrTiO3 spheres were synthesized by a hydrothermal method without using template. ► When titanate nanotube was used as Ti precursor, porous SrTiO3 spheres were generated. ► When titanate nanowire was used as the Ti precursor, solid SrTiO3 spheres were obtained.
Co-reporter:Xilai Jia, Zheng Chen, Xia Cui, Yiting Peng, Xiaolei Wang, Ge Wang, Fei Wei, and Yunfeng Lu
ACS Nano 2012 Volume 6(Issue 11) pp:9911
Publication Date(Web):October 9, 2012
DOI:10.1021/nn303478e
Design and fabrication of effective electrode structure is essential but is still a challenge for current lithium-ion battery technology. Herein we report the design and fabrication of a class of high-performance robust nanocomposites based on iron oxide spheres and carbon nanotubes (CNTs). An efficient aerosol spray process combined with vacuum filtration was used to synthesize such composite architecture, where oxide nanocrystals were assembled into a continuous carbon skeleton and entangled in porous CNT networks. This material architecture offers many critical features that are required for high-performance anodes, including efficient ion transport, high conductivity, and structure durability, therefore enabling an electrode with outstanding lithium storage performance. For example, such an electrode with a thickness of ∼35 μm could deliver a specific capacity of 994 mA h g–1 (based on total electrode weight) and high recharging rates. This effective strategy can be extended to construct many other composite electrodes for high-performance lithium-ion batteries.Keywords: aerosol spray; carbon nanotube; flexible electrode; iron oxide; lithium-ion battery
Co-reporter:Xiaolei Wang;Ge Li;Zheng Chen;Veronica Augustyn;Xueming Ma;Bruce Dunn;Yunfeng Lu
Advanced Energy Materials 2011 Volume 1( Issue 6) pp:1089-1093
Publication Date(Web):
DOI:10.1002/aenm.201100332
Co-reporter:Mu Yang, Ge Wang and Hongtu Ma
Chemical Communications 2011 vol. 47(Issue 3) pp:911-913
Publication Date(Web):15 Nov 2010
DOI:10.1039/C0CC03435E
Polystyrene/poly(4-vinylpyridine) (PS/P4VP) particles with various morphologies such as popcorn-like (A), colloidal molecule NH3 (B), colloidal molecule H2O (C) and mushroom-like (D) were generated by dynamically controlling and stabilizing the phase separation during the seeded swelling polymerization.
Co-reporter:Yingying Wang, Ge Wang, Mu Yang, Li Tan, Wenjun Dong, Rudy Luck
Journal of Colloid and Interface Science 2011 Volume 353(Issue 2) pp:519-523
Publication Date(Web):15 January 2011
DOI:10.1016/j.jcis.2010.09.086
Ti-MCM-41 and Ti-MCM-48 are successfully prepared by one step synthesis and post-synthesis at room temperature. The samples have been characterized by X-ray diffraction, SEM, TEM, nitrogen adsorption/desorption isotherms and UV–Vis spectroscopy. The results demonstrate the existence of an ordered mesoporous structure. The Ti species are grafted into the pure silica sieve frameworks without any evidence of the formation of non-skeleton anatase. The post-synthesis Ti-MCM-41 regular nano-particles display a higher conversion and selectivity as compared to that for both the post-synthesis Ti-MCM-48 and Ti-MCM-41 with ordinary particles, in the epoxidation of cis-cyclooctene with aqueous H2O2 as an oxidant. The enhanced catalytic activity may be attributed to the existence of a higher number of isolated tetracoordinated Ti active sites and regular nano-particles, which are conducive to the affinity of the reactants with active sites.Graphical abstractThe post-synthesis Ti-MCM-41 possesses more isolated tetracoordinated Ti active centers and displayed a highly ordered structure, which facilitates high activity for the epoxidation of cis-cyclooctene with H2O2.Research highlights► The post-synthesis Ti-MCM-41 was synthesized by room temperature grafting methods. ► The post-synthesis Ti-MCM-41 has more isolated tetracoordinated Ti active centers. ► The post-synthesis Ti-MCM-41 displays high activity.
Co-reporter:Xiubing Huang, Wenjun Dong, Ge Wang, Mu Yang, Li Tan, Yanhui Feng, Xinxin Zhang
Journal of Colloid and Interface Science 2011 Volume 359(Issue 1) pp:40-46
Publication Date(Web):1 July 2011
DOI:10.1016/j.jcis.2011.03.049
Ag nanowires within the channels of mesoporous silica have been successfully synthesized via a double solvent technique, in which n-hexane is used as a hydrophobic solvent to disperse mesoporous silica and an AgNO3 aqueous solution is used as a hydrophilic solvent to fill mesochannels. The morphology of the obtained Ag (nanowires, nanoparticles or nanorods) can be controlled by adjusting the concentration of AgNO3 solution and the template pore size. HRTEM images demonstrate extensive Ag nanowires with several to tens of hundreds nanometers in length are deposited along the long axis of mesochannels when the atomic AgNO3/Si ratio is 0.090. When the atomic AgNO3/Si ratio is 0.068 or 0.11, there is a combination of Ag nanoparticles and nanowires; nanoparticles are mainly formed when the atomic AgNO3/Si ratio is higher than 0.14. Further, the catalytic results of the oxidation of styrene show that styrene oxide and benzaldehyde are the main products of the reaction, and the morphology and diversity of Ag in Ag/mesoporous silica composites have an effect on the conversion of styrene and selectivity of styrene oxide.Graphical abstractAg nanowires with several micrometers length have been successfully synthesized within SBA-15 by a simple double solvent method. The morphology and loaded amount of Ag can be controlled by the concentrations of AgNO3.Highlights► Ag nanowires with several micrometers length have been successfully synthesized. ► The amount and morphology of Ag can be controlled by the concentrations of AgNO3. ► The mechanism of Ag formation through the double solvent technique is proposed.
Co-reporter:Xiubing Huang, Mu Yang, Ge Wang, Xinxin Zhang
Microporous and Mesoporous Materials 2011 Volume 144(1–3) pp:171-175
Publication Date(Web):October 2011
DOI:10.1016/j.micromeso.2011.04.012
Co-reporter:Xiubing Huang, Ge Wang, Mu Yang, Wanchun Guo, Hongyi Gao
Materials Letters 2011 Volume 65(19–20) pp:2887-2890
Publication Date(Web):October 2011
DOI:10.1016/j.matlet.2011.06.005
Polyaniline-modified Fe3O4/SiO2/TiO2 composite microspheres have been successfully synthesized by sol–gel reactions on Fe3O4 microspheres followed by the chemical oxidative polymerization of aniline. The synthesized multilayer-structured composites were characterized by TEM, XRD, TGA, UV–vis diffuse reflectance spectra and magnetometer. The photocatalytic activity was evaluated by the photodegradation of methylene blue under visible light. The effect of polyaniline (PANI) amounts on the photocatalytic activity was investigated. The photocatalytic activity results show that the Fe3O4/SiO2/TiO2 composites with about 2.4 wt.%–4.1 wt.% PANI could show higher photocatalytic efficiency than that of Fe3O4/SiO2/TiO2. Furthermore, the PANI-Fe3O4/SiO2/TiO2 photocatalyst could be easily recovered using a magnet.Research highlights► PANI-modified Fe3O4/SiO2/TiO2 photocatalysts have been synthesized. ► The amount of PANI has influence on the photocatalytic activity. ► The photocatalyst can be easily recovered through magnetic action.
Co-reporter:Li Tan, Lijing Cao, Mu Yang, Ge Wang, Dongbai Sun
Polymer 2011 Volume 52(Issue 21) pp:4770-4776
Publication Date(Web):29 September 2011
DOI:10.1016/j.polymer.2011.08.050
In the present work, a simple and effective approach has been employed to fabricate the polystyrene/polyaniline (PS/PANI) composite microspheres with various morphologies. PS/PANI composite microspheres exhibiting different structures such as sea-urchin like, core-shell structure, have been synthesized by seeded emulsion polymerization with polystyrene microspheres as seeds. In particular, the sea urchin-like PS/PANI composite microspheres, with radial array nanofibers on the surface, have demonstrated the switchable wettability between superhydrophilicity (0°) and superhydrophobicity (152°) under the response of either electrical potential or pH. This intelligible approach can produce sea urchin-like PS/PANI composite microspheres in bulk. The growth mechanism of sea urchin-like PS/PANI composite microspheres has also been elucidated. Following the dissolution of the PS template, the sea urchin-like polyaniline (PANI) hollow microspheres are obtained.
Co-reporter:Li-Jing Cao;Lin Shi;Mu Yang ;Dong-Bai Sun
Journal of Applied Polymer Science 2010 Volume 116( Issue 6) pp:3178-3183
Publication Date(Web):
DOI:10.1002/app.31197
Abstract
Poly 4-vinylpyridine (P4VP) microspheres between 170 and 728 nm were synthesized by Emulsifier-Free Emulsion Polymerization. The monomer concentration, ionic strength, and initiator concentration affected the microsphere size and size distribution. The increasing monomer concentration led to the increase of microsphere size, whereas the size distribution of the resultant P4VP microspheres increased with the increasing ionic strength of the reaction systems. Mo(O2)2O·2DMF was successfully anchored onto the P4VP microspheres by ligand exchange, and the heterogeneous catalyst showed high-catalytic activity for epoxidation of cis-cyclooctene with environmentally friendly hydrogen peroxide. The size and morphology of the supported microspheres has important influence on the catalytic activity. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Co-reporter:Lijing Cao;Mu Yang;Yen Wei;Dongbai Sun
Journal of Polymer Science Part A: Polymer Chemistry 2010 Volume 48( Issue 3) pp:558-562
Publication Date(Web):
DOI:10.1002/pola.23760
Abstract
The immobilization of molybdenum (Mo) compounds on poly(4-vinylpyridine) (P4VP) microspheres for catalytic epoxidation was reported. P4VP-supported Mo compounds were highly efficient and selective for the epoxidation of cis-cyclooctene using hydrogen peroxide (H2O2) as oxygen source. When ethanol was used as solvents, outstanding catalytic activity and selectivity were observed for Mo-containing catalysts in the epoxidation of cis-cyclooctene. A completely green epoxidation system based on H2O2 and cleaner solvent has been achieved, and the heterogenized Mo catalyst can be recovered for five times without loss of its activity. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 558–562, 2010
Co-reporter:Jia Li, Ge Wang, Zhan Shi, Mu Yang, Rudy L. Luck
Solid State Sciences 2009 Volume 11(Issue 11) pp:1955-1960
Publication Date(Web):November 2009
DOI:10.1016/j.solidstatesciences.2009.07.009
A crystallographic investigation of anion–π interactions and hydrogen bonds on the preferred structural motifs of molybdenum(VI) complexes has been carried out. Two molybdenum(VI) network polymers MoO2F4·(Hinca)2 (1) and MoO2F3(H2O)·(Hinpa) (2), where inca = isonicotinamide and inpa = isonipecotamide, have been synthesized, crystallographically characterized and successfully applied to alcohol oxidation reaction. Complex 1 crystallizes in the monoclinic space C2/c: a = 16.832(3) Å, b = 8.8189(15) Å, c = 12.568(2) Å, β = 118.929(3)°, V = 1560.1(5) Å3, Z = 4. Complex 2 crystallizes in the triclinic space P-1: a = 5.459(2) Å, b = 9.189(4) Å, c = 12.204(5) Å, α = 71.341(6)°, β = 81.712(7)°, γ = 77.705(7)°, V = 564.8(4) Å3, Z = 2. Complex 1 consists of hydrogen bonding and anion–π interactions, both of which are considered as important factors for controlling the geometric features and packing characteristics of the crystal structure. The geometry of the sandwich complex of [MoO2F4]2− with two pyridine rings indicates that the anion–π interaction is an additive and provides a base for the design and synthesis of new complexes. For complex 2, the anions and the protonated inpa ligands form a 2D supramolecular network by four different types of hydrogen contacts (N–H⋯F, N–H⋯O, O–H⋯F and O–H⋯O). The catalytic ability of complexes 1 and 2 has also been evaluated by applying them to the oxidation of benzyl alcohol with TBHP as oxidant.
Co-reporter:Hangjun Ding, Ge Wang, Mu Yang, Yi Luan, Yingnan Wang, Xingxiong Yao
Journal of Molecular Catalysis A: Chemical 2009 Volume 308(1–2) pp:25-31
Publication Date(Web):4 August 2009
DOI:10.1016/j.molcata.2009.03.038
Novel heterogeneous molybdenum catalysts were successfully synthesized using sea urchin-like polyaniline (PANI) hollow microspheres constructed with their own oriented nanofibers arrays as support. This catalyst was successfully applied for efficient epoxidation of olefins using tert-butylhydroperoxide (TBHP) as oxidant. The catalytic activity of the PANI microspheres-supported catalysts (95% conversion) was found to be higher than that observed for its corresponding homogenous catalyst (85% conversion) and the conventional PANI-supported catalyst (65% conversion). The immobilized catalyst showed a stable catalytic activity in manifold reuses. It was found that the special micro/nanoscale spherical morphology plays an important role for the enhancement of activities of the polymer-supported heterogeneous catalyst.By using sea urchin-like PANI hollow microspheres microspheres as support, a novel polymer-supported molybdenum catalyst was successfully produced. This catalyst was efficiently applied to the epoxidation of wide range of linear and cyclic alkenes. The special micro/nanoscale spherical morphology played an important role in the enhancement of catalytic activity.
Co-reporter:Jia Li;Zhan Shi;Mu Yang;Rudy L. Luck
Structural Chemistry 2009 Volume 20( Issue 5) pp:869-876
Publication Date(Web):2009 October
DOI:10.1007/s11224-009-9485-1
Two molybdenum (VI) hydrogen-bonded network polymers [MoO2F4]·(4,4′-H2bpd)(H2O)2 (1) and [MoO2Cl3(H2O)]·(4,4′-H2bpd)Cl (2) (bpd = bipiperidine) have been synthesized and examined as catalysts for epoxidation of cyclooctene. Complexes of the Mo compounds containing the bpd ligand are prepared and characterized by infrared spectroscopy, thermogravimetric and elemental analyses. They have been structurally characterized by single crystal X-ray diffraction analysis. The structures of both the complexes are shown to be comprised of molybdenum and two protonated N-ligand cations that have resulted in a cross-linked hydrogen-bonded network structure. These complexes are applicable as catalysts for the cis-cyclooctene epoxidation reactions with hydrogen peroxide as a source of oxygen and NaHCO3 as a cocatalyst. It has been observed that the formation of the oxidant peroxymonocarbonate ion, HCO4− by hydrogen peroxide and bicarbonate enhances the epoxidation reaction. Both the complexes have exhibited a good activity and a very high selectivity for the formation of cyclooctene oxide.
Co-reporter:Jia Li;Zhan Shi;Mu Yang;Rudy L. Luck
Structural Chemistry 2009 Volume 20( Issue 6) pp:
Publication Date(Web):2009 December
DOI:10.1007/s11224-009-9515-z
Co-reporter:Yi Luan;Rudy L. Luck;Mu Yang
European Journal of Inorganic Chemistry 2007 Volume 2007(Issue 9) pp:
Publication Date(Web):14 FEB 2007
DOI:10.1002/ejic.200601054
The new hybrid inorganic–organic polymer [MoO2Cl2(H2O)2]·(H2dipy-pra)Cl2 (1), where dipy-pra = 1,3-bis(4-pyridyl)propane, has been synthesized and crystallographically characterized. MoO2Cl2(H2O)2 and the [H2dipy-pra]2+ cation are cross-linked by Mo–H2O···Cl and H2dipy-pra···Cl hydrogen bonds to form a two-dimensional layer structure. Complex 1 is an efficient catalyst, with H2O2 as the oxygen-source oxidant and NaHCO3 as the cocatalyst, in the epoxidation of olefinic compounds under ambient conditions.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Co-reporter:Radoelizo S. Andriamitantsoa, Wenjun Dong, Hongyi Gao, Ge Wang
Chemical Physics Letters (March 2017) Volume 671() pp:
Publication Date(Web):March 2017
DOI:10.1016/j.cplett.2017.01.028
•A novel highly organic polymer for shape-stabilized phase change materials was developed.•A maximum weight percentage as high as 85% has been achieved without leakage of the melted PEG2000.•The composite PCMs were stable in terms of thermal behavior over 50 melting and cooling cycling.A series of porous triamide-linked polymers labeled as PTP were prepared by condensation of 1,3,5-benzenetricarbonyl trichloride with benzene-1,4-diamine (A), 4,4′-methylenediamine (B) and 1,3,5-triazine-2,4,6-triamine (C) respectively. The as-synthesized polymers exhibit permanent porosity and high surface areas which guarantee to hold polyethylene glycol (PEG) molecules in their network for shape-stabilized phase change materials. They possess different effects on the phase change properties of the composite due to their different porosities. PTP-A have intrinsic well-ordered morphology, microstructure and good enough pores to keep the PCMs compared to PTP-B and PTP-C. PEG 2000 used as PCMs could be retained up to 85 wt% in PTP-A polymer materials and these composites were defined as form-stable composite PCMs without the leakage of melted PCM. The thermal study revealed a good storage effect of encapsulated polymer and the enthalpy of melting increases in the order PTP-C < PTP-B < PTP-A at the same PEG content in the blends. The PEG@PTP-A composite at 85% PEG content presented a greater thermal storage capacity. The latent heats for melting and freezing was found to be 155 and 141.7 kJ/kg with a peak appearing at around 53.13 and 29.67 °C respectively. The study suggests that pore size is important for the preparation of shape-stabilized PCMs.A series of 1,3,5-benzenetricarbonyl trichloride cross-linked organic polymer was prepared by condensation with benzene-1,4-diamine (A), 4,4′-methylenediamine (B) and 1,3,5-triazine-2,4,6-triamine (C) respectively which was served to encapsulate PEG 2000 in each framework structure. The PTP-A composite was found to prevent leakage of PEG and have potential high heat storage with excellent recyclability.
Co-reporter:Rui Dang, Xilai Jia, Xin Liu, Hongtu Ma, Hongyi Gao, Ge Wang
Nano Energy (March 2017) Volume 33() pp:
Publication Date(Web):March 2017
DOI:10.1016/j.nanoen.2017.01.024
•The hierarchical Cu nanosheets @ CuO nanorods nanostructures were fabricated by a facile hydrothermal approach.•The hierarchical Cu nanosheets @ CuO nanorods electrodes show a high reversible capacity at a current 0.1C.•Cu nanosheet can effectively buffer the large volume expansion/contraction and improve the electrical contact of the active materials during charge-discharge processes.The hierarchical Cu nanosheets @ CuO nanorods nanostructures were fabricated by a facile hydrothermal approach using Cu nanosheets as self-template and nano-substrate in an aqueous solution of NaOH/H2O2. The hierarchical Cu nanosheets @ CuO nanorods electrodes show a high reversible capacity of 620 mAh/g after 200 cycles, much higher than that of the pure CuO nanocrystals at a current 0.1 C. The excellent electrochemical performance of the hierarchical Cu nanosheets @ CuO nanorods electrode can be attributed to the unique architecture, which not only provides appropriate spaces between nanorod arrays to accommodate the volume change during the discharge/charge process, but also enables fast charge transport owing to the reduced diffusion paths for electrons and induced the Cu nanosheet as the nano-substrates.The hierarchical Cu nanosheets @ CuO nanorods nanostructure is fabricated by a facile hydrothermal approach and the growth mechanisms are investigated. The hierarchical Cu nanosheets @ CuO nanorods electrodes show excellent rate performance and cycling stability for lithium-ion batteries, which can be attribute to their unique architecture.
Co-reporter:Jingjing Wang, Mu Yang, Wenjun Dong, Zhaokui Jin, Jia Tang, Shuang Fan, Yunfeng Lu and Ge Wang
Catalysis Science & Technology (2011-Present) 2016 - vol. 6(Issue 1) pp:NaN168-168
Publication Date(Web):2015/10/08
DOI:10.1039/C5CY01099C
A series of efficient cobalt(II)-anchored Cr-MOF (Cr-MIL-101-NH2) catalysts, such as Co(II)@Cr-MIL-101-Sal, Co(II)@Cr-MIL-101-P2I and Co(II)@Cr-MIL-101-P3I, have been successfully synthesized by one-pot modification of the terminal amino group with salicylaldehyde, pyridine-2-aldehyde or pyridine-3-aldehyde and anchoring of Co(II) ions into the mesoporous Cr-MOF supports. The Co(II)@Cr-MIL-101-P2I catalyst exhibited high catalytic performance for epoxidation of olefins with air as an oxidant due to the nitrogen atom in the pyridine ring as a strong electron-withdrawing substituent, high dispersion of Co(II) species and high surface area for sufficient contact between the substrate and active sites. The strong coordination interaction between the Co(II) ions and chelating groups in the Co(II)@Cr-MIL-101-P2I catalyst guaranteed the excellent recycling performance. Furthermore, the synthesized Co(II)@Cr-MIL-101-P2I catalyst realized its general applicability towards various olefins, such as cyclic olefins, tri-substituted olefins, aliphatic olefins and aromatic olefins.
Co-reporter:Yi Luan, Nannan Zheng, Yue Qi, Jia Tang and Ge Wang
Catalysis Science & Technology (2011-Present) 2014 - vol. 4(Issue 4) pp:NaN929-929
Publication Date(Web):2014/01/06
DOI:10.1039/C3CY00864A
A new thiourea-containing metal–organic framework (MOF) catalyst was synthesized. It overcomes recycling, self-aggregation and solvation issues that exist in homogeneous thiourea catalysts. Nanomorphology was introduced to increase the dispersion of the solid catalyst in solvent. Acetalization and Morita–Baylis–Hillman reactions were catalyzed using the new thiourea MOF catalyst.
Co-reporter:Xiaowei Zhang, Ge Wang, Mu Yang, Yi Luan, Wenjun Dong, Rui Dang, Hongyi Gao and Jie Yu
Catalysis Science & Technology (2011-Present) 2014 - vol. 4(Issue 9) pp:NaN3089-3089
Publication Date(Web):2014/05/09
DOI:10.1039/C4CY00430B
A novel hybrid Fe3O4–CuO@meso-SiO2 catalyst was successfully fabricated by a multi-step assembly method. CuO nanoparticles were first deposited on the surface of Fe3O4 microspheres to form the Fe3O4–CuO hybrid microspheres through a solvothermal reaction. A mesoporous silica (meso-SiO2) shell, with perpendicularly aligned pore channels, was then coated on the hybrid microspheres using sol–gel technology. The Fe3O4 microspheres not only offered fast and effective recycling properties for the catalyst but also acted as electron donors to CuO, leading to a higher electron density on the CuO surface and a subsequently enhanced catalytic performance. The mesoporous silica shell provided strong protection against the aggregation and leaking of the active CuO nanoparticles and also offered appropriate channels for an efficient mass transfer of the catalytic reaction. The Fe3O4–CuO@meso-SiO2 catalyst exhibited excellent activity, convenient magnetic separability and good stability in the catalytic epoxidation of styrene.
Co-reporter:Zheng Chen, Ding Weng, Xiaolei Wang, Yanhua Cheng, Ge Wang and Yunfeng Lu
Chemical Communications 2012 - vol. 48(Issue 31) pp:NaN3738-3738
Publication Date(Web):2012/03/01
DOI:10.1039/C2CC30406F
Thin-film pseudocapacitor electrodes with ultrafast lithium storage kinetics, high capacitance and excellent cycling stability were fabricated from monodispersed TiO2 building nanocrystals, providing a novel approach towards next-generation micro-supercapacitor applications.
Co-reporter:Mu Yang, Ge Wang and Hongtu Ma
Chemical Communications 2011 - vol. 47(Issue 3) pp:NaN913-913
Publication Date(Web):2010/11/15
DOI:10.1039/C0CC03435E
Polystyrene/poly(4-vinylpyridine) (PS/P4VP) particles with various morphologies such as popcorn-like (A), colloidal molecule NH3 (B), colloidal molecule H2O (C) and mushroom-like (D) were generated by dynamically controlling and stabilizing the phase separation during the seeded swelling polymerization.
Co-reporter:Xiaowei Zhang, Wenjun Dong, Yi Luan, Mu Yang, Li Tan, Yangguang Guo, Hongyi Gao, Yinhai Tang, Rui Dang, Jie Li and Ge Wang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 8) pp:NaN4273-4273
Publication Date(Web):2015/01/08
DOI:10.1039/C4TA06046F
A novel catalyst consisting of a functional sulfonated-polystyrene (SPS) core, a porous Cu3(BTC)2 shell and an active Cu(II) interface between the core and shell was developed via a facile step-by-step assembly method. The polystyrene core was sulfonated first to achieve functional –SO3H groups on its surface. The main function of the –SO3H groups was to graft Cu(II) ions to generate an active Cu(II) interface, and the excess –SO3H could provide acid conditions for the catalytic reaction. The Cu(II) interface along with the acid conditions and the co-catalyst 2,2,6,6-tetramethyl-piperidyl-1-oxy (TEMPO) enhanced the catalytic activity for the aerobic oxidation of alcohols to aldehydes by molecular oxygen under base-free conditions. A portion of Cu(II) ions on the SPS surface was then coordinated with H3BTC (1,3,5-benzenetricarboxylic acid) to form a porous Cu3(BTC)2 shell, which could protect the active metal from leaching as well as provide porous channels for mass transfer, resulting in high stability and recyclability in the catalysis procedure. The SPS–Cu(II)@Cu3(BTC)2 catalyst could be recycled ten times without a significant loss in its activity and selectivity. Furthermore, the SPS–Cu(II)@CuBDC (BDC = 1,4-benzenedicarboxylate) composite was also synthesized and showed high efficiency for catalyzing the aerobic oxidation of alcohols and aerobic homocoupling of arylboronic acids, suggesting that the unique nanostructure of SPS–Cu(II)@MOFs can be easily extended to design complex catalysts with high efficiency and good stability for different catalytic reactions.
Co-reporter:Yi Luan, Ming Yang, Qianqian Ma, Yue Qi, Hongyi Gao, Zhenyu Wu and Ge Wang
Journal of Materials Chemistry A 2016 - vol. 4(Issue 20) pp:NaN7649-7649
Publication Date(Web):2016/04/12
DOI:10.1039/C6TA01676F
The design and synthesis of a shape-stabilized composite phase change material (PCM) is the most practical approach for addressing the leakage issue of phase change materials. This manuscript describes a facile solution impregnation method to access a novel type of shape-stabilized PCM employing metal–organic frameworks as the matrix. A fatty acid@metal–organic framework (MOF) composite PCM for low temperature heat storage has been developed for the first time. The metal–organic framework serves as an ideal host material for achieving a composite PCM taking advantage of its highly porous structure and tunable host–guest interactions. PXRD, FTIR, SEM, TGA, BET and DSC characterization studies have been conducted to reveal the structural and thermal properties of the newly achieved PCM composites. The results showed that one-step synthesized MIL-101-NH2 provided the most optimal thermal properties and the highest stearic acid mass percentage was achieved at 70 wt%, which corresponds to the highest loading and highest enthalpy in the literature for organic acid derived shape-stabilized PCMs. Furthermore, the thermal performance of the fatty acid@MOF composite PCM was maintained after 50 cycles, which indicates its great thermal stability.
Co-reporter:Yi Luan, Yue Qi, Hongyi Gao, Radoelizo S. Andriamitantsoa, Nannan Zheng and Ge Wang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 33) pp:NaN17331-17331
Publication Date(Web):2015/07/08
DOI:10.1039/C5TA00816F
In this manuscript, four common transition-metal derived metal–organic frameworks have been extensively investigated as heterogeneous catalyst supports for Knoevenagel condensation reactions. A simple post-synthetic modification strategy was employed for the rapid and facile introduction of a primary alkyl amino group. The resulting novel MOF–RNH2 catalysts showed greatly enhanced Knoevenagel condensation reactivities towards a variety of aldehyde electrophiles. IRMOF-3 proved to be an unsuitable heterogeneous catalyst support due to its fragile nature upon treatment with bases. The novel zirconium based UiO-66–NH–RNH2 and chromium based Cr-MIL-101–NH–RNH2 materials showed excellent catalytic reactivities, while being highly convenient to synthesize. The basic catalytic activity was further extended to the Henry reaction, and excellent catalytic reactivity was achieved. The size-selectivity was also studied to show that the Knoevenagel condensation occurred inside of the porous structure of the MOF catalyst. The recycling properties of zirconium, aluminum and chromium derived MOFs were evaluated and zirconium based UiO-66 and chromium based Cr-MIL-101 showed excellent catalytic efficiency after five reaction cycles.
Co-reporter:Yi Luan, Yue Qi, Hongyi Gao, Nannan Zheng and Ge Wang
Journal of Materials Chemistry A 2014 - vol. 2(Issue 48) pp:NaN20596-20596
Publication Date(Web):2014/09/08
DOI:10.1039/C4TA04311A
In this study, highly dispersed Au nanoparticles have been immobilized on amino-functionalized metal–organic frameworks (MOFs) via a novel absorption/reduction method in solution. The amino functionality of the MOF rapidly coordinated with HAuCl4 and acted as the Au(0) precursor in the absence of protecting agents. The resulting Au@MOF catalyst was well dispersed in aqueous media taking advantage of its well-defined and uniform sizes and nanomorphologies. The as-synthesized Au@MOF catalyst exhibited high catalytic activities in a wide variety of reactions under ambient conditions, such as the base-free aerobic oxidation of alcohols and oxidation/imine formation/reduction reaction sequences. Furthermore, the Au@MOF catalyst can be easily recovered and reused several times without leaching of metals or significant loss of activity.
Co-reporter:Chao Lei, Zheng Chen, Hiesang Sohn, Xiaolei Wang, Zaiyuan Le, Ding Weng, Meiqing Shen, Ge Wang and Yunfeng Lu
Journal of Materials Chemistry A 2014 - vol. 2(Issue 41) pp:NaN17544-17544
Publication Date(Web):2014/09/09
DOI:10.1039/C4TA03715D
Lithium-ion storage materials with significantly improved performance were developed through the hierarchical assemblies of vanadium-based oxide (V2O5 and LiV3O8) nanorods or iron oxide (Fe3O4) nanocrystals using an efficient, continuous aerosol-spray process. Such hierarchically porous spheres, which were made from networks of low-dimension building blocks, result in materials with reduced ion-diffusion length, fast electrolyte diffusion, and structural robustness. Due to their unique hierarchical structure, these spheres exhibit high lithium storage capacity, excellent cycling stability and good rate capability. This work presents a novel synthesis approach toward better lithium-ion storage materials.
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